Drive system

Abstract

To provide a driving system controlling braking.SOLUTION: A system 100 includes circuit legs 126 with resistivity connected to a converter 106 for converting current for a motor 108 to which power is supplied and to a current source 124 that supplies the power to the motor 108 and disposed therebetween. Each circuit leg 126 includes a braking resistor 114 connected to the converter 106. The system 100 also includes a contactor 115 connected to the braking resistor 114 so that the braking resistor 114 exists between the converter 106 and the contactor 115, and a semiconductor switch 116 connected to the contactor 115 so that the contactor 115 exists between the semiconductor switch 116 and the braking resistor 114. During a regenerative braking operation mode of the system while the power is supplied, the regenerative energy from the motor conducts to the braking resistor 114 and is diffused as heat.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] Related Applications This application claims priority to U.S. Provisional Patent Application No. 63 / 077,267, filed September 11, 2020, the disclosure of which is incorporated herein in its entirety. [Background technology]

[0002] The subject matter described herein relates to drive systems that control braking.

[0003] Discussion on technical fields Regenerative and resistive braking in powered systems is useful for decelerating a powered system, such as a vehicle, by reversing current in an electromagnetic device, such as a motor. However, when a powered system enters such a braking mode, the braking process occurs in a discrete step through the use of contactor switches that open and close to control the conduction of current. This can lead to electrical arcing and associated wear on various circuit components of the powered system, such as contactor switches and / or braking resistors. Wear on these components may require increased maintenance along with replacement costs associated with the worn components. Summary of the Invention

[0004] In one or more embodiments, a drive system is provided that may include resistive circuit legs coupled to and disposed between a converter that converts current for a motor of the powered system and a source of current to power the motor. Each of the circuit legs may include a braking resistor coupled to the converter. Each of the circuit legs may include a contactor coupled to the braking resistor such that the braking resistor is between the converter and the contactor. Each of the circuit legs may include a semiconductor switch coupled to the contactor such that the contactor is between the semiconductor switch and the braking resistor. During a regenerative braking mode of operation of the powered system, regenerative energy from the motor may be conducted to the braking resistor and dissipated as heat.

[0005] In another aspect, a drive system is provided that may include a braking resistor coupled to a converter that converts current for a motor of the powered system and several circuit legs coupled to the braking resistor in parallel with each other. Each of the circuit legs may include a contactor and a semiconductor switch coupled to the contactor such that the contactor is between the semiconductor switch and the braking resistor. During a regenerative braking mode of operation of the powered system, regenerative energy from the motor may be conducted to the braking resistor and dissipated as heat, based on which the contactor or semiconductor switch is in a closed state.

[0006] In one or more embodiments, a drive system is provided that may include an inductor. Each of the inductors may be configured to be disposed on board the powered system and to be selectively coupled to a source of a first current and a converter that converts current for a motor of the powered system. Additionally, each of the inductors may be coupled to a node located between a drain of a semiconductor switch and an anode of a diode or a controlled semiconductor switch. Each of the anodes may be coupled to a converter and a contactor that is connected in parallel with each other between the source of the first current and the converter. Furthermore, each of the anodes may be coupled to braking resistors that are connected in parallel with each other, and each of the braking resistors is connected in series with a different contactor between the contactor and the converter. Furthermore, each of the anodes may be coupled to a semiconductor switch that is coupled to the contactor such that the contactor is between the semiconductor switch and the braking resistor. During a regenerative braking mode, a resistive braking mode, or a combination of both modes of the powered system, regenerative current from the motor may be conducted to the braking resistor and dissipated as heat based on which the contactor or first semiconductor switch is in a closed state. [Brief description of the drawings]

[0007] The subject matter of the present invention will be understood on reading the following description of non-limiting embodiments with reference to the attached drawings, in which: [Figure 1] FIG. 2 shows a schematic diagram of the drive system in an engine propulsion mode of operation. [Diagram 2] FIG. 2 shows a schematic diagram of the drive system in boost mode of operation. [Diagram 3] FIG. 2 shows a schematic diagram of the drive system in a dynamic braking mode of operation. [Figure 4] FIG. 2 shows a schematic diagram of the drive system in an engine propulsion mode of operation. [Diagram 5] FIG. 2 shows a schematic diagram of the drive system in boost mode of operation. [Figure 6] FIG. 2 shows a schematic diagram of the drive system in a dynamic braking mode of operation. [Figure 7] FIG. 2 shows a schematic diagram of the drive system in a dynamic braking mode of operation. [Figure 8] FIG. 2 shows a schematic diagram of the drive system in an engine propulsion mode of operation. [Figure 9] FIG. 2 shows a schematic diagram of the drive system in an engine propulsion mode of operation. [Figure 10] FIG. 2 shows a schematic diagram of the drive system in an engine propulsion mode of operation. [Figure 11] 1 illustrates an example method for dynamic braking of a drive system. [Figure 12] 1 illustrates an example method for dynamic braking of a drive system. [Figure 13] 1 illustrates an example method for dynamic braking of a drive system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An embodiment of the subject matter described herein relates to a drive system with braking control. By using semiconductor switches, optionally with contactors and braking resistors, a controlled retard during braking of the powered system may be accomplished. For example, pulsing or opening and closing of the semiconductor switches may allow smaller, more discrete amounts of current to pass through the braking resistor. If the current is too much for one semiconductor switch to handle, another semiconductor switch may handle the current - at least some of the time. For example, one semiconductor switch may handle the current one-third of the time, while another semiconductor switch handles the current the next third of the time, and another semiconductor switch handles the current the remaining third of the time. Taking over the switching action in this manner can provide continuous control over braking of the powered system. The duty cycle of each of the semiconductor switches controls how long current can be passed through the braking resistor. The longer the duty cycle, the longer the semiconductor switch is closed and handling the current. By using solid state switches in conjunction with braking resistors and contactor switches, electrical arcing and wear on individual components may be reduced or eliminated, which may result in a system with fewer moving parts, thereby reducing manufacturing complexity and costs.

[0009] The drive system may include a controller. In one embodiment, a suitable semiconductor switch may be an insulated gate bipolar transistor (IGBT). A suitable contactor may be an electrically controlled switch used to switch power circuits. The contactor may be controlled by a circuit having a lower power level than the switched circuit, such as a 74 volt coil electromagnet controlling a 1000 volt motor switch. In one embodiment, the contactor may be a relay. In another embodiment, the contactor may include one or more features to control and suppress any arcs that are generated when interrupting the current. A suitable braking resistor may include a bank of resistors that can dissipate the current as heat. Other suitable resistors may include devices that receive and / or manage the inflow current. For example, any electrical circuit may have an inherent electrical resistance and may be used, at least to some extent, as a resistive circuit. In one embodiment, the resistive circuit may include one or more energy storage devices. In addition to having an internal electrical resistance, the energy storage devices may act as repositors for the current. In another embodiment, the resistive circuit may accept and discard electrical current through work performed (as an alternative or in addition to heat production). For example, the resistive circuit may include an air compressor, such that when the circuit is energized, the compressor operates an air pump. In another embodiment, the resistive circuit is not on-board the powered system, but is electrically coupled to the powered system, for example, via a catenary or third rail. The off-board resistive circuit may rely on the inherent resistance of the circuit, and / or may include a device that provides a load, and / or may include an energy storage device. In a non-limiting example, the powered system may be a vehicle, a wind turbine, or other system that includes a motor. In other non-limiting examples, the motor may be used for propulsion, such as a traction motor, or may be used for other purposes, such as rotating blades in a fan, wind turbine, etc.

[0010] 1, 2 and 3 show the operation of a first embodiment of the drive system in engine propulsion mode, boost propulsion mode and dynamic braking mode, respectively. Two sources of current are included in the shown schematic diagrams: an on-board source and an off-board source. Alternatively, the drive system may have another on-board source, such as a battery, instead of the off-board source. The off-board source of current (124) may be a power source, such as an electric rail or a catenary. The on-board source may be the engine-alternator set (102), an energy storage device or a battery. The off-board source of current is connected to a positive bus (111) and a negative bus. The positive bus connects the source of current to a switch (122) and an inductor (120). The switch is located between the source of current and the inductor.

[0011] The inductor is connected to the collector of the semiconductor switch (116) and to the anode of a diode (118). The cathode of the diode is connected in parallel to a circuit leg (126) that includes the contactor switch (115) and the braking resistor (114). A corresponding node (128) is located between the contactor switch and the semiconductor switch. In the circuit leg, the contactor and the braking resistor are connected in series with each other. The circuit leg is connected in parallel to the diode. The cathode of the diode and the circuit leg with the braking resistor and the contactor are linked to a direct current to alternating current (DC-AC) converter (106) by a positive bus. The DC-AC converter is connected to the motor (108) by another positive bus (145) and another negative bus (140). A capacitor (110) is connected in parallel to the diode, the circuit leg, and the DC-AC converter. An off-board current source is connected to the emitter of the semiconductor switch by a negative bus. The negative bus is connected to a capacitor and to a DC-AC converter. The rectifier (104) is connected to the DC-AC converter by another positive bus and another negative bus. In the embodiment shown, the motor is a traction motor. Optionally, the motor need not be a traction motor that generates torque to propel the vehicle. For example, the motor could power a pump or perform a task other than propulsion.

[0012] In the engine propulsion mode of operation illustrated by FIG. 1, a contactor disposed between a source of current and the inductor is open, which does not conduct current from the source of current. The engine-alternator set generates power to a rectifier for providing power to a motor. Current flow (130) is conducted from the engine-alternator set to the motor. The rectifier may convert AC voltage from the engine-alternator set to DC and provide current to charge a capacitor. The current is conducted to a DC-AC converter. The DC-AC converter may convert the incoming DC to AC and provide current to the motor. The motor uses the AC to propel the powered system.

[0013] FIG. 2 illustrates the drive system in a boost mode of operation. In boost mode, a contactor switch disposed between a current source and an inductor is closed, allowing current flow from the current source along the positive bus. The current source generates power to the inductor, where energy may be stored. The current may be conducted through a diode to provide power to the motor. A capacitor may be charged as it is connected to the current source via the negative bus, and the motor may receive the current.

[0014] FIG. 3 shows the drive system in a dynamic braking mode of operation. The dynamic braking mode may be a regenerative braking mode, a resistive braking mode, or a combination of both modes. In the regenerative or resistive braking modes, or a combination of both modes, the contactor switch located between the current source and the inductor is open and does not conduct current to the motor from the off-board power source. However, the contactor switch located in the circuit leg is closed and conducts current from the motor through the braking resistor and the semiconductor switch. Regenerative energy from the motor is conducted to the braking resistor and dissipated as heat. This configuration with the closed switch between the current source and the inductor may be referred to as the on-state. The current flow of the circuit is shown as conducting from the motor along the positive bus of the drive system (300) through the semiconductor switch. The current is then conducted along the negative bus to the capacitor, to the DC-AC converter, and back to the motor. In this embodiment, the capacitor discharges, and the motor provides the voltage of this embodiment. The semiconductor switches can be adjusted to open and close at high speeds. The high speed pulsing of the semiconductor switches allows the braking to be a smooth and controlled retard. For example, when a contactor located in a circuit leg is closed, the pulsing or opening and closing of the semiconductor switches can allow smaller, more discrete amounts of current to pass through the braking resistor. If the current is too much for one semiconductor switch to handle, another semiconductor switch may be configured to handle at least some of the current. For example, one semiconductor switch may handle the current one-third of the time, while another semiconductor switch handles the current another third of the time, and another semiconductor switch handles the current the remaining third of the time. Taking over the switching action in this manner can provide continuous control over the braking of the powered system. The duty cycle of each of the semiconductor switches measures how long current is allowed to pass through the braking resistor. A longer duty cycle represents a longer time that the semiconductor switch is closed and handling the current.The use of solid state switches in conjunction with braking resistors and contactor switches reduces arcing and wear on individual components, and reducing moving parts reduces manufacturing complexity and cost.

[0015] 4-7 illustrate the operation of an embodiment of the drive system in engine propulsion mode, boost propulsion mode, and dynamic braking mode, respectively. The illustrated schematic diagram includes two sources of current: an on-board source of current and an off-board source of current. Alternatively, the drive system may have another on-board source of current, such as a battery, instead of the off-board source of current. The source of current (424) may be a power source, such as an electric rail or catenary. The on-board source (402) may be an engine-alternator set, an energy storage device (e.g., a battery), etc. The source of current is connected to a positive bus (411) and a negative bus (412). The positive bus connects the source of current to a switch (422) and an inductor (420). The switch is located between the source of current and the inductor.

[0016] The inductor is connected to the collector of the first semiconductor switch (416) and the emitter of the second semiconductor switch (418). The collector of the second semiconductor switch is connected in parallel to a circuit leg (426) including a contactor switch (415) and a braking resistor. A corresponding node (428) is disposed between the contactor switch and the first semiconductor switch. In the circuit leg, the contactor and the braking resistor are connected in series with each other. The circuit leg is connected in parallel to a second semiconductor switch. The collector of the second semiconductor switch and the circuit leg having the braking resistor and the contactor are coupled to a direct current to alternating current (DC-AC) converter (406) by a positive bus. The DC-AC converter is connected to the motor (408) by another positive bus (445) and another negative bus (440). A capacitor (410) is connected in parallel to the second semiconductor switch, the circuit leg, and the DC-AC converter. An off-board source of current is connected to the emitter of the first semiconductor switch by a negative bus. The negative bus is connected to a capacitor and to a DC-AC converter. The rectifier (404) is connected to the DC-AC converter by another positive bus and another negative bus. In the embodiment shown, the motor is a traction motor.

[0017] In the engine propulsion mode of operation illustrated by FIG. 4, the engine-alternator set generates power to a rectifier to provide power to a motor. Current flow (430) is conducted from the engine-alternator set to the motor. The rectifier may convert AC voltage from the engine-alternator set to DC and provide current to charge a capacitor. The current is conducted to a DC-AC converter. The DC-AC converter may convert the incoming DC to AC and provide current to the motor. The motor uses the AC to propel the powered system.

[0018] FIG. 5 illustrates the drive system in a boost mode of operation. In boost mode, a contactor switch disposed between a source of current and an inductor is closed, allowing current flow from the source of current along the positive bus. The source of current generates power to the inductor, where energy may be stored. The current may be conducted through a second semiconductor switch to provide power to the motor. A capacitor may be charged as it is connected to the source of current via the negative bus, and the motor may receive the current.

[0019] FIG. 6 illustrates the drive system in a dynamic braking mode of operation. The dynamic braking mode may be a regenerative braking mode, a resistive braking mode, or a combination of both modes. In the regenerative braking mode, the resistive braking mode, or a combination of both modes, the contactor switch located between the source of current and the inductor is closed and conducts current to an off-board source of current. However, the contactor switch located in the circuit leg is open and does not conduct current through the braking resistor. The current flow of the circuit is shown, conducting through the semiconductor switches from the motor (load), along the positive bus of the drive system to the DC-AC converter, along another positive bus to the capacitor. The first semiconductor switch may conduct current. The second semiconductor switch may be rapidly adjusted to open and close. The rapid pulsing of the second semiconductor switch allows the braking to be a smooth and controlled retard. For example, when the contactor located in the circuit leg is closed, the pulsing or opening and closing of the first semiconductor switch may allow a smaller, more discrete amount of current to pass through the braking resistor. If the current is too much for the first semiconductor switch to handle, another semiconductor switch may be configured to handle at least some of the current. For example, the first semiconductor switch may handle the current one-third of the time, while another semiconductor switch handles the current another third of the time, and another semiconductor switch handles the current the remaining third of the time. Taking over the switching action in this manner can provide continuous control over the braking of the powered system. The duty cycle of each of the semiconductor switches determines how long current is allowed to pass through the braking resistor. A longer duty cycle represents a longer time that the semiconductor switch is closed and handling the current. Using semiconductor switches in conjunction with braking resistors and contactor switches reduces arcing and wear on individual components, and reduces manufacturing complexity and cost by reducing moving parts.The current flow can continue to be conducted to an off-board source of current and return along the negative bus towards the motor, through the emitter of the semiconductor, the capacitor, the connection to the DC-AC converter, and back along another negative bus to the motor, in this embodiment the capacitor is discharged and the motor provides the voltage in this embodiment.

[0020] FIG. 7 shows the drive system in a dynamic braking mode of operation. The dynamic braking mode may be a regenerative braking mode, a resistive braking mode, or a combination of both modes. In the regenerative braking mode, the resistive braking mode, or a combination of both modes, the contactor switch located between the source of current and the inductor is open and does not conduct current to the off-board source of current. However, the contactor switch located in the circuit leg is closed and conducts current from the motor through the braking resistor and the first and second semiconductor switches. The second semiconductor switch may simply conduct current, while the first semiconductor may be rapidly modulated to open and close. The regenerative energy from the motor is conducted to the braking resistor and dissipated as heat. The rapid pulsing of the first semiconductor switch allows the braking to be a smooth and controlled retard. For example, with the contactor located in the circuit leg in a closed state, the pulsing or opening and closing of the first semiconductor switch may allow smaller, more discrete amounts of current to pass through the braking resistor. If the current exceeds a predetermined threshold limit for a first semiconductor switch to handle, another semiconductor switch may handle at least some of the current. For example, a first semiconductor switch may handle the current one-third of the time, while another semiconductor switch handles the current another third of the time, and another semiconductor switch handles the current the remaining third of the time. Taking over the switching action in this manner can provide continuous control over braking of the powered system. The duty cycle of each of the semiconductor switches determines how long current is allowed to pass through the braking resistor. A longer duty cycle represents a longer time that the semiconductor switch is closed and handling current. Using semiconductor switches in conjunction with braking resistors and contactor switches reduces arcing and wear on individual components, and reduces manufacturing complexity and cost by reducing moving parts. The current flow of the circuit can be conducted from the semiconductor switch along the negative bus of the drive system (700), through a capacitor, a DC-AC converter, and along another negative bus to the motor.In this embodiment, a capacitor is discharged and a motor provides the voltage in this embodiment.

[0021] FIG. 8 illustrates the operation of an embodiment of the drive system. The drive system may operate in engine propulsion mode, boost propulsion mode, or dynamic braking mode, respectively. The illustrated schematic includes two sources of current: an on-board source of current and an off-board source of current. Alternatively, the drive system may have another on-board source, such as a battery, instead of the off-board source. The off-board source of current (824) may be a power source, such as an electric rail or catenary. The on-board source may be an engine-alternator set (802), an energy storage device, or a battery. The off-board source of current may be connected to a positive bus (811) and a negative bus (812). The positive bus connects the source of current to a switch (822) and a number of inductors (820) connected in parallel with each other. The switch is located between the source of current and the number of inductors. Each inductor of the plurality of inductors is connected to a collector (816) of a semiconductor switch of the plurality of semiconductor switches and to an anode (818) of a diode of the plurality of diodes. The cathodes of the plurality of diodes are connected in parallel to a circuit leg (826), the circuit leg (826) including a plurality of contactor switches (815) and a plurality of braking resistors (814). A corresponding node (828) is disposed between the plurality of contactor switches and the plurality of semiconductor switches. In at least some of the plurality of circuit legs, the contactor and the braking resistor are connected in series with each other. The plurality of circuit legs are connected in parallel with the plurality of diodes. The cathodes of the plurality of diodes and the plurality of circuit legs having the braking resistors and the contactors may be coupled to a direct current-alternating current (DC-AC) converter (806) by a positive bus. The DC-AC converter may be connected to the motor (808) by another positive bus (845) and another negative bus (840). The capacitor (810) can be connected in parallel to the diodes, the circuit legs, and the DC-AC converter. An off-board source of current can be connected to the emitters of the semiconductor switches by a negative bus. The negative bus can be connected to the capacitor and the DC-AC converter.In the embodiment shown, the motor is a traction motor.

[0022] In an engine propulsion mode of operation, the engine-alternator set generates power to a rectifier (804) for providing power to a motor. The contactors are open, so current is conducted from the engine-alternator set to the motor. The rectifier can convert the AC voltage from the engine-alternator set to DC and provide current to charge a capacitor. The current is conducted to a DC-AC converter. The DC-AC converter can convert the incoming DC to AC and provide current to the motor. The motor can use the AC current to propel the powered system.

[0023] Alternatively, the drive system may operate in a boost propulsion mode. In the boost mode, a contactor switch disposed between the current source and the inductors is closed, conducting current from the current source along the positive bus. The contactors disposed in the resistive circuit legs are open. The current source generates power to the inductors, where energy may be stored. The current source may be an off-board power source, such as an electric rail or catenary, or may be an on-board current source, such as an energy storage device or battery. The current may be conducted through the diodes to provide power to the motor. A capacitor may be charged since it is connected to the current source via the negative bus, and the motor may receive the current.

[0024] Alternatively, the drive system may operate in a dynamic braking mode. The dynamic braking mode may be a regenerative braking mode, a resistive braking mode, or a combination of both modes. In the regenerative braking mode, the resistive braking mode, or a combination of both modes, the contactor switch disposed between the source of current and the inductor is open and does not conduct current from the off-board source of current. However, at least one of the contactor switches disposed in the circuit leg is closed and conducts current from the motor through the corresponding braking resistors and the corresponding semiconductor switches. Regenerative energy from the motor may be conducted to at least some of the braking resistors and dissipated as heat. The semiconductor switches may be rapidly coordinated to open and close. The rapid pulsing of the semiconductor switches allows the braking to be a smooth and controlled retard. For example, with a closed contactor disposed in the circuit leg, the pulsing or opening and closing of the semiconductor switch may allow smaller, more discrete amounts of current to pass through the braking resistor. If the current is too much for one semiconductor switch to handle, another semiconductor switch may be configured to handle at least some of the current. For example, one semiconductor switch may handle the current one-third of the time, while another semiconductor switch handles the current another third of the time, and another semiconductor switch handles the current the remaining third of the time. Taking over the switching action in this manner can provide continuous control over the braking of the powered system. The duty cycle of each of the semiconductor switches determines how long current is allowed to pass through the braking resistor. A longer duty cycle represents a longer time that the semiconductor switch is closed and handling the current. Using semiconductor switches in conjunction with braking resistors and contactor switches reduces arcing and wear on individual components, and reduces manufacturing complexity and cost by reducing moving parts. Current is conducted from the multiple semiconductor switches along the negative bus of the drive system (800) to a capacitor, to a DC-AC converter, and then to the motor.In this embodiment, a capacitor is discharged and a motor provides the voltage in this embodiment.

[0025] FIG. 9 illustrates the operation of an embodiment of the drive system. The drive system may operate in engine propulsion mode, boost propulsion mode, or dynamic braking mode, respectively. The illustrated schematic includes two sources of current: an on-board source of current and an off-board source of current. Alternatively, the drive system may have another on-board source, such as a battery, instead of the off-board source. The off-board source of current (924) may be a power source, such as an electric rail or catenary. The on-board source may be an engine-alternator set (902), an energy storage device, or a battery. The off-board source of current may be connected to a positive bus (911) and a negative bus (912). The positive bus connects the source of current to a switch (922) and a number of inductors (920) connected in parallel with each other. The switch is located between the source of current and the number of inductors. Each inductor of the plurality of inductors is connected to a collector (916) of a semiconductor switch of the plurality of semiconductor switches and to an anode (918) of a diode of the plurality of diodes. The cathodes of the plurality of diodes are connected in parallel to a circuit leg (926), the circuit leg (926) including a braking resistor (914) connected in series with the other plurality of circuit legs that are connected in parallel. The other plurality of circuit legs each include a contactor (915). The circuit leg having the braking resistor and the plurality of contactors connected in parallel with each other is connected in parallel with the plurality of diodes. A corresponding node (928) is disposed between the plurality of contactor switches and the plurality of semiconductor switches. The cathodes of the plurality of diodes and the circuit leg having the braking resistor and the plurality of contactors connected in parallel with each other can be coupled to a direct current to alternating current (DC-AC) converter (906) by a positive bus. The DC-AC converter can be connected to the motor (908) by another positive bus (945) and another negative bus (940). A capacitor (910) may be connected in parallel to the diodes, the circuit legs, and the DC-AC converter. An off-board source of current may be connected to the emitters of the semiconductor switches by a negative bus.The negative bus may be connected to a capacitor and to a DC-AC converter.In the embodiment shown, the motor is a traction motor.

[0026] In an engine propulsion mode of operation, the engine-alternator set generates power to a rectifier (904) to provide power to the motor. The contactors are open, so current is conducted from the engine-alternator set to the motor. The rectifier can convert the AC voltage from the engine-alternator set to DC and provide current to charge a capacitor. The current is conducted to a DC-AC converter. The DC-AC converter can convert the incoming DC to AC and provide current to the motor.

[0027] Alternatively, the drive system may operate in a boost propulsion mode. In the boost mode, a contactor switch disposed between the source of current and the multiple inductors is closed, conducting current from the source of current along the positive bus. The multiple contactors disposed in the circuit legs are open. The source of current generates power to the multiple inductors, where energy may be stored. The source of current may be an off-board power source, such as an electric rail or catenary, or may be an on-board source of current, such as an energy storage device or battery. The current may be conducted through multiple diodes to provide power to the motor. A capacitor may be charged since it is connected to the source of current via the negative bus, and the motor may receive the current.

[0028] Alternatively, the drive system may operate in a dynamic braking mode. The dynamic braking mode may be a regenerative braking mode, a resistive braking mode, or a combination of both modes. In the regenerative braking mode, the resistive braking mode, or a combination of both modes, the contactor switch disposed between the source of current and the multiple inductors is open and does not conduct current from the off-board source of current. The regenerative current from the motor is conducted to the braking resistor and dissipated as heat. However, at least one of the multiple contactor switches disposed in the circuit leg is closed and conducts current from the motor through the braking resistor and the corresponding multiple semiconductor switches. The multiple semiconductor switches can be adjusted to open and close at high speed. The high speed pulsing of the semiconductor switches allows the braking to be a smooth and controlled retard. For example, with a closed contactor disposed in the circuit leg, the pulsing or opening and closing of the semiconductor switch may allow a smaller, more discrete amount of current to pass through the braking resistor. If the current is too much for one semiconductor switch to handle, another semiconductor switch may be configured to handle at least some of the current. For example, one semiconductor switch may handle current one third of the time, while another semiconductor switch handles current another third of the time, and another semiconductor switch handles current the remaining third of the time. Taking over the switching action in this manner can provide continuous control over the braking of the powered system. The duty cycle of each of the semiconductor switches determines how long current is allowed to pass through the braking resistor. A longer duty cycle represents a longer time that the semiconductor switch is closed and handling current. The use of semiconductor switches in conjunction with braking resistors and contactor switches reduces arcing and wear on individual components, and reduces manufacturing complexity and cost by reducing moving parts. Current is conducted from the multiple semiconductor switches along the negative bus of the drive system (900), to a capacitor, to a DC-AC converter, and to a motor. In this embodiment, the capacitor discharges, and the motor provides the voltage in this embodiment.

[0029] FIG. 10 illustrates the operation of an embodiment of the drive system. The drive system may operate in engine propulsion mode, boost propulsion mode, or dynamic braking mode. The schematic diagram shown includes two sources of current: an on-board source of current and an off-board source of current. Alternatively, the drive system may have another on-board source, such as a battery, instead of the off-board source. The off-board source of current (1024) may be a power source, such as an electric rail or catenary. The on-board source may be an engine-alternator set (1002), an energy storage device, or a battery. The off-board source of current may be connected to a positive bus (1011) and a negative bus (1012). The positive bus connects the source of current to a switch (1022). The positive bus connects the source of current to a circuit leg that is connected in series to a number of other circuit legs (1026) that are connected in series with each other. In each of the plurality of circuit legs, the contactor (1015) and the braking resistor (1014) are connected in series with each other. The positive bus connects to a plurality of inductors (1020), which are connected in parallel with each other. The switch is located between the source of current and the plurality of inductors. Each inductor of the plurality of inductors is connected to a collector (1016) of a semiconductor switch of the plurality of semiconductor switches and to an anode (1018) of a diode of the plurality of diodes. The cathodes of the plurality of diodes are connected in parallel to a circuit leg, which includes the plurality of contactor switches and the plurality of braking resistors. A corresponding node (1028) is located between the plurality of contactor switches and the plurality of semiconductor switches. The plurality of circuit legs are connected in parallel with the plurality of diodes. The cathodes of the plurality of diodes and the plurality of circuit legs having the braking resistors and the contactor may be coupled to a direct current to alternating current (DC-AC) converter (1006) by a positive bus. The DC-AC converter can be connected to the motor (1008) by a separate positive bus and a separate negative bus. A capacitor (1010) can be connected in parallel with the diodes and the DC-AC converter. An off-board source of current can be connected to the emitters of the semiconductor switches by the negative bus.The negative bus can be connected to a capacitor and to a DC-AC converter. The rectifier (1004) can be connected to the DC-AC converter by another positive bus (1045) and another negative bus (1040). In the embodiment shown, the motor is a traction motor.

[0030] In an engine propulsion mode of operation, the engine-alternator set generates power to a rectifier for providing power to a motor. The contactors are open, so current is conducted from the engine-alternator set to the motor. The engine-alternator set may be powered by a fuel, such as diesel. The engine-alternator set may provide AC for auxiliary electrical needs, such as lighting. The rectifier may convert the AC voltage from the engine-alternator set to DC and provide current to charge a capacitor. The current is conducted to a DC-AC converter. The DC-AC converter may convert the incoming DC to AC and provide current to the motor.

[0031] Alternatively, the drive system may operate in a boost propulsion mode. In the boost mode, a contactor switch disposed between the source of current and the multiple inductors is closed, conducting current from the source of current along the positive bus. The multiple contactors are open. The source of current generates power to the multiple inductors disposed in the circuit legs, where energy may be stored. The source of current may be an off-board power source, such as an electric rail or catenary, or may be an on-board source of current, such as an energy storage device or battery. The current may be conducted through multiple diodes to provide power to the motor. A capacitor may be charged as it is connected to the source of current via the negative bus, and the motor may receive the current.

[0032] Alternatively, the drive system may operate in a dynamic braking mode. The dynamic braking mode may be a regenerative braking mode, a resistive braking mode, or a combination of both modes. In the regenerative braking mode, the resistive braking mode, or a combination of both modes, the contactor switch disposed between the source of current and the inductor is open and does not conduct current from the off-board source of current. However, at least one of the contactor switches disposed in the circuit leg is closed and conducts current from the motor through the braking resistor, the corresponding inductors, and the corresponding semiconductor switches. Regenerative energy from the motor is conducted to the braking resistor and dissipated as heat. The semiconductor switches can be rapidly adjusted to open and close. The rapid pulsing of the semiconductor switches allows the braking to be a smooth and controlled retard. For example, with a closed contactor disposed in the circuit leg, the pulsing or opening and closing of the semiconductor switch can allow smaller, more discrete amounts of current to pass through the braking resistor. If the current is too much for one semiconductor switch to handle, another semiconductor switch may be configured to handle at least some of the current. For example, one semiconductor switch may handle the current one-third of the time, while another semiconductor switch handles the current another third of the time, and another semiconductor switch handles the current the remaining third of the time. Taking over the switching action in this manner can provide continuous control over the braking of the powered system. The duty cycle of each of the semiconductor switches determines how long current is allowed to pass through the braking resistor. Alternatively, the semiconductor switches can be switched on and off simultaneously. A longer duty cycle represents a longer time that the semiconductor switch is closed and handling the current. Using semiconductor switches in conjunction with braking resistors and contactor switches reduces arcing and wear on individual components, and reduces manufacturing complexity and cost by reducing moving parts. Current is conducted from the multiple semiconductor switches along the negative bus of the drive system (1000) to a capacitor, a DC-AC converter, and then to the motor.In this embodiment, a capacitor is discharged and a motor provides the voltage in this embodiment.

[0033] FIG. 11 provides an example of a method of regenerative braking, resistive braking, or a combination of both in the drive system shown in FIG. 8. At (1102), regenerative energy is conducted from the motor. For example, the motor may act as a power source for the drive system. The motor may act like a generator, providing energy previously provided by another power source, such as a battery. Current from the motor is conducted from the motor to a DC-AC converter. The current may be alternating current (AC). The current may be conducted to the DC-AC converter along a positive bus located between the motor and the DC-AC converter. The DC-AC converter may convert the AC to direct current (DC).

[0034] At (1104), current is conducted from the DC-AC converter to the capacitor along a separate positive bus. For example, current may be conducted between the DC-AC converter and the capacitor along a positive bus different from the bus located between the motor and the DC-AC converter. Alternatively, current may be conducted from the DC-AC converter along the same bus located between the motor and the DC-AC converter.

[0035] At (1106), the capacitor discharges. For example, in a regenerative braking mode, a resistive braking mode, or a combination of both modes, the energy stored by the capacitor may flow out along the positive bus. The current may be conducted toward multiple braking resistors.

[0036] At (1108), the current is conducted by the closed contactors to the braking resistors and dissipated as heat. For example, at least one of the contactor switches is closed and causes the current to be conducted through the corresponding braking resistors along the positive bus. The current may not be conducted to the diode along the positive bus due to the forward bias nature of the diode. In this embodiment, the diode may be oriented such that the current flow in a particular circuit leg is restricted. Alternatively, another semiconductor switch, such as an IGBT, may be used that is actuated to conduct the current bidirectionally through the component.

[0037] At (1110), current is conducted through a plurality of semiconductor switches. For example, pulsing or opening and closing of the semiconductor switches may allow smaller, more discrete amounts of current to pass through the braking resistor. If the current is too much for one semiconductor switch to handle, another semiconductor switch may be configured to handle at least some of the current. For example, one semiconductor switch may handle the current one-third of the time, while another semiconductor switch handles the current another third of the time, and another semiconductor switch handles the current the remaining third of the time. Taking over the switching action in this manner can provide continuous control over the braking of the powered system. The duty cycle of each of the semiconductor switches determines how long current is allowed to pass through the braking resistor. A longer duty cycle represents a longer time that the semiconductor switch is closed and handling the current. Using the semiconductor switches in conjunction with the braking resistor and contactor switch reduces arcing and wear on individual components. And by reducing moving parts, manufacturing complexity and cost is reduced. The other power source may be bypassed by a closed contactor during regenerative braking mode, so that current is conducted along the drive system negative bus to the capacitor.

[0038] At (1112), current is conducted to a capacitor. For example, the current is conducted along a negative bus that is connected to the end of the capacitor that is not connected to the positive bus. The current is conducted along the negative bus through the capacitor connection to a DC-AC converter.

[0039] At (1114), current is conducted along the negative bus to a DC-AC converter. For example, the negative terminal of the DC-AC converter is connected to the negative bus. The DC-AC converter can convert DC to AC as required by the motor during regenerative braking mode, resistive braking mode, or a combination of both modes. Current is conducted from the DC-AC converter towards the motor.

[0040] At (1116), current is conducted to the motor. For example, the current may be conducted along a separate negative bus from the DC-AC converter. Alternatively, the current may be conducted along the same negative bus that is connected to other circuit components. For a regenerative braking mode, the motor provides power to the drive system. The system may operate in this mode as needed to provide controlled braking and smooth retardation.

[0041] FIG. 12 provides an example of a method of regenerative braking, resistive braking, or a combination of both in the drive system shown in FIG. 9. At (1202), regenerative energy is conducted from the motor. For example, the motor may act as a power source for the drive system. The motor may act like a generator, providing energy previously provided by another power source, such as a battery. Current from the motor is conducted from the motor to a DC-AC converter. The current may be alternating current (AC). The current may be conducted to the DC-AC converter along a positive bus located between the motor and the DC-AC converter. The DC-AC converter may convert the current to direct current (DC).

[0042] At 1204, current is conducted from the DC-AC converter to the capacitor along a separate positive bus. For example, current may be conducted between the DC-AC converter and the capacitor along a positive bus different from the bus located between the motor and the DC-AC converter. Alternatively, current may be conducted from the DC-AC converter along the same bus located between the motor and the DC-AC converter.

[0043] At (1206), the capacitor discharges. For example, in a regenerative braking mode, a resistive braking mode, or a combination of both modes, the energy stored by the capacitor may flow out along the positive bus. Current may continue to be conducted toward the braking resistor.

[0044] At (1208), the current is conducted by the closed contactor to the braking resistor and dissipated as heat. For example, the braking resistor may be connected in series with multiple contactors connected in parallel with each other. At least one of the multiple contactors is closed and causes the current to be conducted through the braking resistor along the positive bus. The current may not be conducted to the diode along the positive bus due to the forward bias nature of the diode. In this embodiment, the diode may be oriented such that the current flow in a particular circuit leg is limited. Alternatively, another type of semiconductor switch, such as an IGBT, may be used that is actuated to conduct the current bidirectionally through the component.

[0045] At (1210), the current is conducted through a number of semiconductor switches. For example, pulsing or opening and closing the semiconductor switches may allow smaller, more discrete amounts of current to pass through the braking resistor. If the current is too much for one semiconductor switch to handle, another semiconductor switch may be configured to handle at least some of the current. For example, one semiconductor switch may handle the current one-third of the time, while another semiconductor switch handles the current another third of the time, and another semiconductor switch handles the current the remaining third of the time. Taking over the switching action in this manner can provide continuous control over the braking of the powered system. The duty cycle of each of the semiconductor switches determines how long the current is allowed to pass through the braking resistor. A longer duty cycle represents a longer time that the semiconductor switch is closed and handling the current. Using semiconductor switches in conjunction with braking resistors and contactor switches reduces arcing and wear on individual components, and reduces manufacturing complexity and cost by reducing moving parts. The other power source may be bypassed by a closed contactor during regenerative braking mode, resistive braking mode, or a combination of both modes, so that current is conducted along the negative bus of the drive system to the capacitor.

[0046] At 1212, current is conducted to a capacitor. For example, the current is conducted along a negative bus that is connected to the end of the capacitor that is not connected to the positive bus. The current is conducted along the negative bus through the capacitor connection to a DC-AC converter.

[0047] At (1214), current is conducted along the negative bus to a DC-AC converter. For example, the negative terminal of the DC-AC converter is connected to the negative bus. The DC-AC converter can convert DC to AC as required by the motor during regenerative braking mode, resistive braking mode, or a combination of both modes. Current is conducted from the DC-AC converter towards the motor.

[0048] At (1216), current is conducted to the motor. For example, the current may be conducted along a separate negative bus from the DC-AC converter. Alternatively, the current may be conducted along the same negative bus that is connected to other circuit components. For a regenerative braking mode, a resistive braking mode, or a combination of both modes, the motor provides power to the drive system. The system may operate in this mode as needed to provide controlled braking and smooth retardation.

[0049] FIG. 13 provides an example of a method of regenerative braking, resistive braking, or a combination of both in the drive system shown in FIG. 9. At (2), regenerative energy is conducted from the motor. For example, the motor may act as a power source for the drive system. The motor may act like a generator, providing energy previously provided by another power source, such as a battery. Current from the motor is conducted from the motor to a DC-AC converter. The current may be alternating current (AC). The current may be conducted to the DC-AC converter along a positive bus located between the motor and the DC-AC converter. The DC-AC converter may convert the current to direct current (DC).

[0050] At 1304, current is conducted from the DC-AC converter to the capacitor along a separate positive bus. For example, current may be conducted between the DC-AC converter and the capacitor along a positive bus different from the bus located between the motor and the DC-AC converter. Alternatively, current may be conducted from the DC-AC converter along the same bus located between the motor and the DC-AC converter.

[0051] At 1306, the capacitor discharges. For example, in a regenerative braking mode, a resistive braking mode, or a combination of both modes, the energy stored by the capacitor may flow out along the positive bus. Current may continue to be conducted toward multiple braking resistors.

[0052] At (1308), the current is conducted by the closed contactor to the braking resistors and dissipated as heat. For example, the braking resistors may be connected in series with the contactors connected in parallel with each other. At least one of the contactors is closed and causes the current to be conducted through the braking resistor along the positive bus. The current may not be conducted to the diode along the positive bus due to the forward bias nature of the diode. In this embodiment, the diode may be oriented such that the current flow in a particular circuit leg is restricted. Alternatively, another type of semiconductor, such as an IGBT, may be used that operates to conduct the current bidirectionally through the component. The current is conducted to the inductors through the resistive circuit legs connected in parallel with each other.

[0053] At 1310, current is conducted through multiple inductors. For example, the multiple inductors may be connected in parallel with each other and in series with the multiple resistive legs. The stored energy in the multiple inductors may be discharged in a regenerative braking mode, a resistive braking mode, or a combination of both modes. Current may be conducted from the multiple inductors to multiple semiconductor switches along a positive bus.

[0054] At (1312), the current is conducted through a number of semiconductor switches. For example, pulsing or opening and closing the semiconductor switches may allow smaller, more discrete amounts of current to pass through the braking resistor. If the current is too much for one semiconductor switch to handle, another semiconductor switch may be configured to handle at least some of the current. For example, one semiconductor switch may handle the current one-third of the time, while another semiconductor switch handles the current another third of the time, and another semiconductor switch handles the current the remaining third of the time. Taking over the switching action in this manner can provide continuous control over the braking of the powered system. The duty cycle of each of the semiconductor switches determines how long the current is allowed to pass through the braking resistor. A longer duty cycle represents a longer time that the semiconductor switch is closed and handling the current. Using semiconductor switches in conjunction with braking resistors and contactor switches reduces arcing and wear on individual components, and reduces manufacturing complexity and cost by reducing moving parts. The other power source may be bypassed by a closed contactor during regenerative braking mode, resistive braking mode, or a combination of both modes, so that current is conducted along the negative bus of the drive system to the capacitor.

[0055] At 1314, current is conducted to the capacitor. The current is conducted along a negative bus, e.g., the negative bus is connected to the end of the capacitor that is not connected to the positive bus. The current is conducted along the negative bus, through the capacitor connection, and to the DC-AC converter.

[0056] At (1316), current is conducted along the negative bus to a DC-AC converter. For example, the negative terminal of the DC-AC converter is connected to the negative bus. The DC-AC converter can convert DC to AC as required by the motor during regenerative braking mode, resistive braking mode, or a combination of both modes. Current is conducted from the DC-AC converter towards the motor.

[0057] At (1318), current is conducted to the motor. For example, the current may be conducted along a separate negative bus from the DC-AC converter. Alternatively, the current may be conducted along the same negative bus that is connected to other circuit components. For a regenerative braking mode, a resistive braking mode, or a combination of both modes, the motor provides power to the drive system. The system may operate in this mode as needed to provide controlled braking and smooth retardation.

[0058] In one or more embodiments, a system is provided that may include resistive circuit legs coupled to and disposed between (a) a converter that converts current for the motor and (b) a source of current to power the motor. Each of the circuit legs may include a braking resistor coupled to the converter. Each of the circuit legs may include a contactor coupled to the braking resistor such that the braking resistor is between the converter and the contactor, and a first semiconductor switch coupled to the contactor such that the contactor is between the first semiconductor switch and the braking resistor. During a regenerative braking mode, a resistive braking mode, or a combination of both regenerative braking and resistive braking modes, regenerative current from the motor may be conducted to the braking resistor and dissipated as heat.

[0059] Optionally, each of the contactors may be configured to be individually controlled to alternate between (a) an open state in which a corresponding braking resistor coupled to the contactor is disconnected from a corresponding node, and (b) a closed state in which a braking resistor corresponding to and coupled to the contactor is connected to the corresponding node of the contactor.

[0060] Optionally, each of the braking resistors may be configured to dissipate at least a portion of the regenerative current from the motor as heat while the corresponding contactor is in a closed state. Optionally, each of the braking resistors may be configured to dissipate at least a portion of the regenerative current from the motor as heat while the corresponding first semiconductor switch is in a closed state. Optionally, each of the contactors may be configured to conduct at least a portion of the regenerative current from the motor through a capacitor while the contactor is in an open state. Optionally, (a) one or more diodes or (b) a second semiconductor switch may be connected in parallel with each other and with the contactors and the braking resistor between a source of current and the converter. Optionally, the source of current may be one or more of an electric rail or a catenary or an energy storage device. Optionally, (a) one or more inductors, (b) one or more diodes or second semiconductor switches, (c) a contactor, and (d) a braking resistor may be connected in parallel with the converter, the alternator and the rectifier.

[0061] In another aspect, a system is provided that may include a braking resistor coupled to a converter that converts current for a motor of a powered system and a number of circuit legs coupled to the braking resistor in parallel with each other. Each of the circuit legs may include a contactor and a first semiconductor switch coupled to the contactor such that the contactor is between the first semiconductor switch and the braking resistor. During a regenerative braking mode or a resistive braking mode of operation of the powered system, regenerative energy from the motor of the powered system may be conducted to the braking resistor and dissipated as heat based on which (a) the contactor or (b) the first semiconductor switch is in a closed state.

[0062] Optionally, the contactor may be connected in parallel with each other between the off-board source of current and the braking resistor. Optionally, one or more inductors may be connected in parallel with each other and with the contactor and the braking resistor between the source of current and the converter. Optionally, (a) one or more diodes or (b) a second semiconductor switch may be connected in parallel with each other and with the contactor and the braking resistor between the off-board source of current and the converter. Optionally, the source of current may be one or more of an electric rail or a catenary or an energy storage device. Optionally, (a) the inductor, (b) one or more diodes or one or more second semiconductor switches, (c) the contactor, and (d) the braking resistor are connected to the converter in parallel with the alternator and the rectifier. Optionally, a capacitor is connected to the converter in parallel with the alternator and the rectifier.

[0063] In one or more embodiments, a system is provided that may include two or more inductors, one or more first semiconductor switches, and one or more second semiconductor switches. Each of the inductors may be disposed on-board the powered system and may be selectively coupled to an off-board power source and a converter, which converts current for a motor of the powered system. Additionally, each of the inductors may be coupled to a node located between a cathode of a first semiconductor switch of the one or more first semiconductor switches and (a) an anode of a diode or (b) an emitter of a second semiconductor switch of the one or more second semiconductor switches. Each of the anodes and emitters may be coupled to the converter, contactors connected in parallel with each other between a source of current and the converter. Additionally, the anodes or emitters may be coupled to braking resistors connected in parallel with each other, each of the braking resistors being connected in series with a different contactor between the contactor and the converter. Further, each of the anodes may be coupled to a first semiconductor switch coupled to the contactor such that the contactor is between the first semiconductor switch and the braking resistor. During a regenerative or resistive braking mode of the powered system, regenerative energy from the motor may be conducted to the braking resistor and dissipated as heat based on which the contactor or the first semiconductor switch is in a closed state.

[0064] Optionally, the two or more inductors and (a) the diode or (b) the second semiconductor switch may be connected in parallel with the contactor and the braking resistor between the source of current and the converter. Optionally, the source of current may be one or more of an electric rail or a catenary or an energy storage device. Optionally, the (a) two or more inductors, (b) the diode or the second semiconductor switch, (c) the contactor, and (d) the braking resistor may be connected in parallel with the converter and with the alternator and the rectifier. Optionally, a capacitor is connected in parallel with the converter and with the alternator and the rectifier.

[0065] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly indicates otherwise. "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and the description may include the occurrence or non-occurrence of the event. As used throughout this specification and claims, approximation language may be applied to modify any quantitative expression that may vary within permissible limits without changing the basic function that may be involved. Thus, values ​​modified by terms such as "about," "substantially," and "approximately" may not be limited to the precise values ​​specified. In at least some cases, approximation language may correspond to the precision of the instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and / or interchanged, and unless otherwise indicated by context or language, such ranges are identified and include all subranges contained therein.

[0066] This written description uses examples to disclose embodiments of the invention, including the best mode, and to enable one of ordinary skill in the art to practice the embodiments of the invention, including making and using any device or system, and performing any methods encompassed. The claims define the patentable scope of the disclosure, and include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal words of the claims, or if they include equivalent structural elements with differences that do not differ insubstantially from the literal words of the claims.

Claims

1. 1. A system comprising: At least one resistive circuit leg coupled to and disposed between (a) a converter that converts a first current for a motor, and (b) a source of the first current for powering the motor, the at least one resistive circuit leg comprising: A braking resistor; a contactor coupled to the braking resistor. at least one resistive circuit leg; a first semiconductor switch coupled to the at least one resistive circuit leg and disposed in parallel with the at least one resistive circuit leg; a second semiconductor switch coupled to the first semiconductor switch and to the at least one resistive circuit leg; Including, the at least one resistive circuit leg is coupled to the first semiconductor switch and the second semiconductor switch at a location between the first semiconductor switch and the second semiconductor switch; During a regenerative braking mode, during a resistive braking mode, or during a combination of both the regenerative braking mode and the resistive braking mode, the contactor is closed and the first semiconductor switch is controlled to alternate between an open state and a closed state to conduct at least some of the regenerative current from the motor to the braking resistor to control braking by the motor.

2. 2. The system of claim 1, wherein during the regenerative braking mode, during the resistive braking mode, or during a combination of both the regenerative braking mode and the resistive braking mode, the contactors are closed and the first semiconductor switches are individually controlled to alternate between the open state and the closed state, while the second semiconductor switches are configured to close.

3. The system of claim 1 , wherein the braking resistor is configured to dissipate at least a portion of the regenerative current from the motor as heat.

4. 3. The system of claim 2, wherein the first semiconductor switch is configured to conduct at least a portion of the regenerative current from the motor through a capacitor while the first semiconductor switch is in the open state, the capacitor being disposed between (a) the first and second semiconductor switches and (b) the converter and in parallel with the at least one resistive circuit leg.

5. The system of claim 1 , wherein the first source of the first current is one or more of an electric rail, a catenary, or an energy storage device.

6. 1. A system comprising: a positive bus configured to be connected to a source of current; a negative bus configured to be connected to the source of the current; a braking resistor coupled to the positive bus; a number of parallel circuit legs, each including a contactor, connected in series with said braking resistor; a number of semiconductor switches connected in parallel with each other, each of which is connected in series with a different one of the number of parallel circuit legs between the positive bus and the negative bus; Including, the positive bus and the negative bus are coupled to a converter that converts current for a motor of a system to be powered; During a regenerative or resistive braking mode of a powered system, regenerative current from the motor is conducted to the braking resistor and dissipated as heat, and different ones of the number of semiconductor switches close at different times while other ones of the number of semiconductor switches remain open.

7. 7. The system of claim 6, further comprising a plurality of inductors connected in parallel with one another between the source of the current and the circuit legs, each of the plurality of inductors being connected to a different one of the circuit legs.

8. 7. The system of claim 6, wherein the source of the electric current is one or more of an electric rail, a catenary, or an energy storage device.

9. The system of claim 6 , wherein a capacitor is connected in parallel with the converter and the circuit leg to the positive bus and the negative bus.

10. 1. A system comprising: one or more first semiconductor switches; one or more second semiconductor switches; two or more inductors, each inductor of the two or more inductors configured to be disposed onboard a powered system and selectively coupled to a source of a first current and a converter that converts the first current for a motor of the powered system, each of the two or more inductors coupled to a node located between the one or more first semiconductor switches and either (a) one or more diodes or (b) the one or more second semiconductor switches, the second semiconductor switches coupled to the converter; a plurality of contactors connected in parallel with each other between the source of the first current and the converter; braking resistors connected in parallel with each other, each braking resistor being connected in series with a different one of the plurality of contactors between a contactor and the converter; wherein the first semiconductor switch of the one or more first semiconductor switches is coupled to a contactor of the plurality of contactors connected in parallel with each other such that one contactor of the plurality of contactors connected in parallel with each other is between the first semiconductor switch of the one or more first semiconductor switches and the braking resistor; wherein during a regenerative braking or resistive braking mode of operation of the powered system, regenerative current from the motor of the powered system is conducted to the braking resistor and dissipated as heat, based on which the plurality of contactors or the one or more first semiconductor switches are in a closed state.

11. 11. The system of claim 10, wherein the two or more inductors and (a) the diode or (b) the second semiconductor switch are connected in parallel with the plurality of contactors and the braking resistor between the first current source and the converter.

12. The system of claim 10 , wherein the source of the first current is one or more of an electric rail, a catenary, or an energy storage device.

13. 11. The system of claim 10, wherein (a) the two or more inductors, (b) the diode or the second semiconductor switch, (c) the plurality of contactors, and (d) the braking resistor are connected in parallel with the converter, an alternator and a rectifier.

14. 11. The system of claim 10, wherein a capacitor is connected in parallel with the converter, the alternator and the rectifier.

Images